Protective device for envelops.



T. WATANABE.

PROTECTIVE DEVICE FOR ENVELOPS.

APPLIOATION FILED SBPT.28, 1911.

1,065,012, Patented June 17,1913.

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TETSUSABURO VIATANABE, OF NEW YORK, N. Y.

PROTECTIVE DEVICE FOR ENVELOPS.

Application filed September 23, 1911.

To all whom 2'15 may concern:

Be it known that I, TETSUSABURO TATA- NABE, a subject of the Emperor of Japan, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Protective Devices for Envelops, of which the following is a specification.

The invention is a paper envelop having in the overlapping portion of its sealing flap an integral section of thinner material, which section, after the envelop has been scaled, will become broken when any attempt is made to open the envelop, and the fact of such attempt will then be revealed by the mutilation of said section.

In the accompanying drawings-Figure 1 represents a paper envelop, having an in tegral section of reduced thickness in its sealing flap. Fig. 2 is a section on the line :0, as of Fig. 1. Fig. 3 represents a paper envelop having an integral section of reduced thickness and of ornamental configuration in its sealing flap. Fig. 1 represents a paper envelop with an integral portion of its seal ing flap reduced in thickness by abrasion. Fig. 5 is a section on the line 2 y of Fig. 4. Fig. 6 represents a paper envelop with several integral sections in its sea-ling flap, each of reduced thickness.

Similar letters of reference indicate like parts. 1

A represents a paper envelop of the usual form, and B, the sealing flap which is secured to the body of the envelop by any suitable adhesive material, such as mucilage, which may be applied to the under side of the flap and dried there, in the usual way. In Figs. 1 and 3 the width of the portion of the sealing flap covered by dried mucilage is the distance bet-ween the edge of the flap and the dotted line a, a.

In the part of the sealing flap which is to adhere to the envelop body, I produce a weaker section C. This I may do in various ways: as, for example, by subjecting the paper, which is to form the thin section, to pressure while the sheet is in process of manufacture, and so rendering it thinner, as indicated in Figs. 1, 2, 3 and 6; or by remov- Specification of Letters Patent.

Patented June 17, 1913.

Serial No. 650,950.

ing in any suitable manner, as by abrading, the surface of the section for a suitable depth, as indicated in Figs. 4 and5. When such a section is present in the sealing flap, and the adhesive material forming the seal is softened sufliciently to permit that part of the flap which is not thinned or otherwise treated, as described, to be detached from the place of adhesion without rupture, the thinned portion will still remain sufliciently adherent to be torn by the same strain which detaches the rest of the flap, and in fact the stronger paper may be broken away from the section, leaving more or less of the latter still secured by the paste. That this has been done is plainly apparent on inspection, and thus any tampering with the sealed envelop is plainly revealed.

I may make the section of any suitable ornamental. configuration and thus measurably conceal its real obj ectas, for example, producing it in the form of an initial letter, or letters, or in some arbitrary distinctive pattern, as shown in Fig. 8.

I am aware that envelops have been made with inserted sections of thin paper, and also that portions of the sealing flaps of envelops have been weakened by the making of perforations or slits therein, and I am also aware that it has been proposed to treat portions of envelop flaps with acid in order to weaken the material, but none of these expedients are claimed by me.

I claim:

1. A paper envelop, having a section of thinner material formed in and integrally with the overlapping portion of its sealing flap.

2. A paper envelop, having a section of thinner material formed in and integrally with the overlapping portion of its sealing flap,.and a coating of adhesive material on said flap and section.

In testimony whereof I have afiixed my signature in presence of two witnesses.

TETSUSABURO IVATANABE.

Witnesses GERTRUDE T. PORTER,

MAY T. MOGARRY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

